A Dynamic Bootstrap Voltage Technique for a High-Efficiency Buck Converter in a Universal Serial Bus Power Delivery Device

Abstract

The dynamic bootstrap voltage (DBV) technique is proposed to keep high efficiency over wide ranges of load currents for high-power universal serial bus devices. The silicon area of the embedded power management with the DBV technique in the system-on-a-chip can be effectively reduced to 50% of the conventional design with a P-type high-side power MOSFET. Test chips fabricated in 0.25-mu m CMOS process showed a 92% peak efficiency from 1 mA to 1 A. The maximum driving current was higher than 5 A, and the efficiencywas 88%. Compared with the efficiency of the converter without the DBV technique, the efficiency of the converter with DBV technique was improved by about 28%.